Fix: install curl in runtime image for Coolify healthcheck

The container ran fine (uvicorn started on :8000) but Coolify's healthcheck
runs `curl` / `wget` inside the container, neither of which ships in
python:3.13-slim. Container marked unhealthy → rolled back.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -19,11 +19,10 @@ ENV PYTHONUNBUFFERED=1 \
 
 WORKDIR /app
 
-# Build deps for curl_cffi (needs libcurl-impersonate). curl_cffi vendors
-# its own libs but a C toolchain is still useful for any pure-Python whls
-# without prebuilt wheels for slim.
+# gcc — for any pure-Python wheels without prebuilt slim wheels.
+# curl  — Coolify runs its healthcheck via curl inside the container.
 RUN apt-get update \
-    && apt-get install -y --no-install-recommends gcc \
+    && apt-get install -y --no-install-recommends gcc curl \
     && rm -rf /var/lib/apt/lists/*
 
 # Install Python deps from pyproject.